Owing to diversification of the fitting location, miniaturization, quietness, and high operational stability in sensing an optical disc, etc. are often demanded of the optical disc device as in the onboard one, for example.
An optical disc device 100 of this type will be explained with reference to FIG. 12 to FIG. 14 hereunder. In FIG. 12, 101 is a box-type case, and a disc slot is formed in a front plate 101A of the case 101. Also, 102 is a disc loading roller arranged in vicinity of the disc slot, and this roller 102 is turned by a roller driving mechanism (not shown) to insert/eject a disc 103. Also, 104 is a semi-annular tray for holding the disc 103, and plural sheets of trays 104 are stacked in the case 101 on the corner portion side between a rear plate 101B and a right side plate 101C (see JP-A-2000-40290, FIG. 1, FIG. 8, FIG. 10, for example).
A metal plate 105 is arranged on the uppermost side and the lowermost side of plural sheets of trays 104 respectively, and a hole is formed in the tray 104 and the metal plates 105 at three locations respectively. Three tray guiding shafts both ends of each of which are fixed to a top plate and a bottom plate of the case 101 respectively are inserted into the holes of the tray 104 and the metal plates 105. Therefore, plural trays 104 and the metal plates 105 can be guided by three tray guiding shafts to move vertically. Also, 106 is a lever that is supported turnably in the case 101, and a roller 107 is fitted to a top end of this lever 106.
The lever 106 is energized clockwise (FIG. 12) by a spring (not shown). The disc 103, after inserted through the disc slot formed in a center of the front plate 101A, is transferred toward the rear plate 101B in the case 101 by the roller 102. The roller 107 fitted to the top end of this lever 106 contacts an outer peripheral surface of the disc 103 in the middle of this transfer. Therefore, the direction of the disc is changed to the tray 104 and then the disc 103 is loaded in the tray 104.
In the optical disc device 100, the disc 103 moved to a center of the case 101 pushes the roller 107 on the lever 106 as shown in FIG. 13 such that the lever 106 is turned on a shaft 108 counterclockwise in FIG. 12. In FIG. 13, 106A is a projection formed integrally on an upper surface of the lever 106, and 109 is a photo coupler a light emitting device and a photo detector of which are arranged to face to each other.
When a motor for moving an elevator mechanism that causes a plurality of trays 104 to ascend/descend is rotated, a turning/driving force of the motor is transferred to a cam gear 110 shown in FIG. 12 and FIG. 14 via a reduction gear mechanism, and then the cam gear 110 is rotated. Then, the disc 103 when pushed by a projection 111 of the cam gear 110 to a center of the case 101 pushes the roller 107, and then the lever 106 is turned counterclockwise. Then, the projection 106A is released from the photo coupler 109, so that the photo coupler 109 is shifted from OFF to ON. As described above, it is sensed whether or not the disc 103 is present on the tray 104 in such a manner that the projection 111 of the cam gear 110 is inserted sequentially between the trays in the course of lowering plural sheets of trays 104 by the tray elevating mechanism and then it is sensed by the photo coupler 109 whether or not the lever 106 is turned at an insertion timing. Here, in FIG. 14, 110A is a helical cam groove, and 110B, 110C are cam threads of the cam gear 110.